class_docstr: defines how to transform encoder to decoder
  
  # Arguments
  bridge_type: currently only support "dense | densenonlinear"
  decoder_hiddenSize: hidden size of decoder
  bridge: keras layers used to do the transformation
  
  >>> bridge = Bridge.initialize("dense", 2)
  creating: createZooKerasBridge
  >>> dense = Dense(3)
  creating: createZooKerasDense
  >>> bridge = Bridge.initialize_from_keras_layer(dense)
  creating: createZooKerasBridge
docstr: bridge_type: currently only support "dense | densenonlinear"
  decoder_hiddenSize: hidden size of decoder
docstr_tok: ["bridge_type",":","currently","only","support","``","dense","|","densenonlinear","''","decoder_hiddenSize",":","hidden","size","of","decoder"]
code: def initialize(cls, bridge_type, decoder_hidden_size):
      """
      bridge_type: currently only support "dense | densenonlinear"
      decoder_hiddenSize: hidden size of decoder
      """
      return Bridge(bridge_type, decoder_hidden_size, None)
  
imports: from bigdl.nn.layer import Layer
  from zoo.pipeline.api.keras.layers import *
  from zoo.models.common import ZooModel
  from zoo.common.utils import callZooFunc
  from zoo.pipeline.api.keras.engine import ZooKerasLayer
  from zoo.pipeline.api.keras.models import Model
label_desc: Use image node_id 2 for calling the Bridge obj's underlying member method code with example usage: obj.initialize(cls, bridge_type, decoder_hidden_size) and returns: Bridge